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E. S. JONES. DEVICE FOR STRAINING zmo PLATES TO THEIR BEDS.

No. 478,607. Patented July 12, 1892.

WK WQTHLOT Fig.8

21/2777 asses UNITED STATES EDIVARD S. JONES, OF PROVIDENCE, RHODE ISLAND.

DEVICE FOR STRAINING ZINC PLATES TO THEIR BEDS.

SPECIFICATION forming part of Letters Patent No. 478,607, dated July 12, 1892. Application filed November 17, 1891. gerial No. 412,214. (No model.)

To aZZ whom it may cancer-m Be it known that I, EDWARD S. JONES, of

. Providence, in the State of Rhode Island, have made certain new and useful Improvements in Devices for Straining Zinc Plates to Their Beds; and I do hereby declare that the following specification, taken in connection with the drawings, making a part of the same, is a full, clear, and exact descriptionthereof.

Figure l is a side view of clamping-jaws with plate secured between the same. Fig. 2 isa rear View of the same. Figs. 3 and at show parts of clamp separated. Fig. 5 shows the straining device. Fig. 6 shows the several parts assembled. Fig. 7 is a rear view of same. Fig. 8 is a rear view of part of mechanism.

The object of my invention is to produce a straining device by which the plate may be more easily and readily adjusted to its bed; and it consists in the construction, arrange ment, and operation of the separable mechanism for that purpose hereinafter described.

The devices now in use for straining plates to their beds are attached to and form a part of the bed and its supporting sides. This attachment necessitates the securing and releasing of the plate from the holding-jaws every time it is used. As the same plate may be frequently required, the time and labor expended in fastening and unfastening the clamps is considerable and seriously interferes with the rapidity of the work. To overcome these difficulties, I separate the parts of my device into two divisions, one of which is fastened to and goes with the plate, while the other is attached to and forms a part of the bed,the two divisions being easily and quickly united to operate together in straining the plate.

The clamps are constructed in two parts A and B, Figs. 1, 2, 3, and 4, and are fastened to the opposite edges of the plate at equal distances from each other by means of a screwbolt F. The cooperation of the parts A and B are more fully insured by an extension D of the jaw A, which fits into a recess E of the jaw B. This operation of attaching the clamps to the plate may be performed before the latter is placed upon the bed, and they may remain upon and be removed with the plate when it is taken off.

G, 5, is the bed, and II the straininglever hinged thereto and having a hook J at the upper end.

I is a straining-screw working through the lever H and forcing the latter off by means of contact with the supporting side of the bed G.

O O are trunnions upon either side of the clamps, and Z is the zinc plate.

The operation of my improved device is as follows: The clamps having been once attached. to the plate, as shown in Figs. 1 and 2, and the straining-lever being in the position indicated in Fig. 5, the plate is placed upon the bed and the trunnions O C placed within the hooks J. The lever H is next forced off by turning the screw I, as shown in Fig. 6, in a manner already understood, which brings the plate into close and complete contact with the bed, more or less strain being exerted on the screws, as may be required, to make the plate smooth. Whenever any particular plate is done with, the screw I is turned back,bringing the lever H to a nearly-vertical position,when the trunnions O C may be disconnected from the hooks J and the plate, with its clamps, may be removed and laid away for future use. By means of the trunnions 0 C, working in the hooks J, the direction of strain is always coincident with the angle of the plate.

WVhat Iv claim as my invention, and desire to secure by Letters Patent, is-

1. In a straining device for lithographic plates, the combination of a lever H, having a hook J at its upper end, a clamp detachably secured in said hook, the screw I, and the bed G, the whole constructed and operating together in a manner and for the purposes described.

2. The combination of a, clamp composed of two parts, one of which parts is provided with a trunnion at each end, a straining-lever having hooks at its upper end adapted to re- .ceive the trunnions of the clamp, and means for operating the lever, the whole constructed and arranged to permit of the detachment of the plate from its bed without removing the clamps, as and for the purposes specified.

3. In combination, a bed-plate having a straining-lever permanently secured thereto and a clamp detachably secured to the lever, means for operating the clamp independently of the connection between the clamp and the lever, whereby the clamp may be detached from the lever Without releasing its hold upon i the plate and without detaching the lever from the bed-plate, and means for operating 1c the lever, substantially as and for the purpose set forth.

4. The clamps A B, constructed with trun= nions O O, in combination with the hooked lever H and screw I, the whole constructed and arranged to operate and permit the detachment of the plate from its bed, as described.

EDWARD S. JONES.

Witnesses:

WALTER B. VINCENT, JOSEPH H. FLAHERTY. 

